BEETLES
    Beetles belong to the order Coleoptera. The front wings of beetles are hard, tough, or horny sheaths (elytra); these meet in a straight line down the middle of the back and cover the hind wings. Hind wings are membranous and usually longer than the front wings. Beetles have chewing mouth parts; antennae usually have 8-10 segments, tarsi usually 3-5 segments, and the abdomen has 5 segments. Beetles have complete metamorphosis; the egg hatches into a soft grub (larvae), most often with six legs, sometimes it is legless; the grub eventually turns into a pupa with the sacs holding the appendages freely movable and finally the pupa turns into the adult beetle. Some species of beetles are injurious to crops only in the adult stage, while other species are injurious to crops only in the larval stage, and some species are injurious to crops in both the adult and larval stage.
 

Argus Tortoise Beetle (Chelymorpha cassidea): The adult beetle is yellow to brick-red with 15 to 20 small rounded black spots on the forward two-thirds of the back, around 1/3 inch long, very convex, and the margins of the body are not extended. Larvae are yellow with many small brown spots, 1/2 inch long, and have long marginal spines that are black-tipped. Larval and adult forms both cause damage.

 

Asiatic Garden Beetle (Maladera castanea): Adults are cinnamon-brown, 3/8 inch long, have fine longitudinal striae on the wing covers and a fine pubescence which gives them a velvety appearance. Larvae are grayish with light brown heads and around 3/4 inch long; they differ from japanese beetle grubs by having the spines at the tip of the abdomen arranged in a semicircle rather than a V and by having more slender bodies. Adult damage can be seen as irregular holes at the margins of leaves; grubs feed mostly on roots.

Asparagus Beetle (Crioceris asparagi): Adults are brilliantly colored with bluish-black straight sided wing covers, each with three large, yellowish, squarish spots along each side and reddish margins, have a reddish prothorax and head, and are around 1/4 inch long. Larvae are dull gray with black heads and legs, plump, soft, wrinkled, and about 1/2 inch long. Adult beetles eat the tender buds and cause scars to form; larvae migrate to the tips of leaves and feed there. Eggs appear as specks, dark brown, and shiny on foliage.

Asparagus Beetle

Larva

Banded Cucumber Beetle (Diabrotica balteata): Adult beetles are light green with three bands of darker green.

Bean Leaf Beetle (Cerotoma trifurcata): Adult beetles are reddish to yellowish in color, 1/4 inch long, have three or four black spots in a row along the inner edge of wing covers, and a black band occurs near the outer margins of wing covers. Larvae are whitish, dark brown at both ends, segmented, and have six small legs near the head. Adults chew holes in leaves, feeding on them from the under surface; larvae feed on roots, nodules, and on stems just below the soil surface, which can girdle the plant.

Beet Leaf Beetle (Erynephala puncticollis): Adults are dull yellow with black margins, have black spots on the thorax, and are 1/3 inch long. Larvae are grayish or olive-brown marked with raised tubercles and yellow spots. Both larvae and adults feed on the foliage of plants.

Blister Beetles (Epicauta spp.): Adults are slender, about four times as long as wide, rather soft with the head distinctly set off from the prothorax and the tip of the abdomen exposed beyond the tip of the wing covers; they are black or grayish in color with narrow yellowish or gray stripes or margins on the wings. Only the adults damage plants; they feed on the foliage. Common blister beetles that can often be seen on plants include the Ashgray Blister Beetle, Black Blister Beetle, Margined Blister Beetle, and Striped Blister Beetle.

Striped Blister Beetle

Black Blister Beetle

Bumble Flower Beetle (Euphoria inda): The adult resembles a bumblebee; it is 1/2 inch long, broadly oval, yellowish-brown mottled with black. Only adults cause damage to plants.

Carrot Beetle (Bothynus gibbosus): Adult beetles are reddish-brown with stout legs, broad, and about 1/2 inch long; they damage plants by gouging out roots and base of stems. Larvae are bluish-white with brown heads; larvae feed on the roots of plants.

Cereal Leaf Beetle (Oulema melanopa): Adult beetles have black heads, reddish-brown midsections, metallic blue backs, and are around 1/4 inch long; adult beetles cause damage to crops.

Colorado Potato Beetle (Leptinotarsa decemlineata): Adult beetles can be recognized by the alternate black and yellow stripes that run lengthwise on the wing covers, five of each color on each wing cover; they are about 3/8 inch long by 1/4 inch wide. Larvae are brick-red in color, black spotted, soft skinned, humpbacked, have a swollen head, and are around 1/2 inch long. Both the adults and larvae feed by chewing the leaves and terminal growth of plants.

Colorado Potato Beetle

Larva

Corn Sap Beetle (Carpophilus dimidiatus): A very small, brown scavenger beetle that eats corn kernels; this beetle gets into the ear after the husk is loosened by birds or after earworms have feed on the ear.

Corn Silk Beetle (Calomicrus brunneus): Adult beetles are oval to circular, very convex, have their heads sunk in the prothorax almost to the eyes, antennae are widely separated at the base, and feed on corn silks.

Small Darkling Ground Beetle (Metoponium abnorme): Adults are black or dark brown, smooth, around 1/3 inch long, and have slightly reddish legs. Adult beetles injure the fruit of some vegetables.

Dusky Sap Beetle (Carpophilus lugubris): Similar to the corn sap beetle; it injures corn kernels, but it is usually associated with damage caused by other insects.

False Potato Beetle (Leptinotarsa juncta): Similar to the colorado potato beetle; it is usually found on potatoes.

Fig Beetle (Cotinis mutabilis): Adult beetles are green to copper or violet, flat, broad, large, and around 1 inch long. Adults feed on the fruits of a few vegetables.

Flea Beetles: Flea beetles are small leaf beetles and named for their habit of jumping like fleas when they are disturbed; adult flea beetles feed on the foliage of plants which can be seen as tiny shot holes in the foliage. The various species of flea beetles that are pests of vegetables include the banded flea beetle, cabbage flea beetle, corn flea beetle (transmits bacterial wilt of corn), desert flea beetle, eggplant flea beetle, hop flea beetle, pale striped flea beetle, red-headed flea beetle, potato flea beetle, sinuate flea beetle, spinach flea beetle, striped flea beetle, sweet potato flea beetle, tobacco flea beetle, toothed flea beetle, tuber flea beetle, western black flea beetle, western striped flea beetle, and western potato flea beetle.

Larvae

Black Flea Beetle

Flea Beetle Damage

Eggplant Flea Beetle

Hop Flea Beetle

Sinuate Flea Beetle

Potato Flea Beetle

Spinach Flea Beetle

Sweet Potato Flea Beetle

Fuller Rose Beetle (Pantomorus cervinus): Adult beetles are weevils, about 1/3 inch long with a short broad snout, a white diagonal stripe occurs across each wing cover, and they form ragged areas on the margins of leaves. Larvae are white to yellowish with a brown head, legless, and feed on roots of plants which cause the foliage to turn yellow.
 

Golden Tortoise Beetle (Metriona bicolor): Adult beetles are oval, around 1/4 inch long, look like drops of molten gold often called gold bugs, and the margins of their bodies are extended so as to hide their heads and most of their legs. Larvae are dull brown with about thirty thorny spines on their bodies, up to 3/8 inch long, and their backs are completely covered with a dirty mass of excrement and shed skins. Both adults and larvae eat holes in the foliage.

Golden Tortoie Beetle (left)

Grape Colaspis (Colaspis brunnea): The adults are small, palebrown, elliptical, and covered with rows of punctures. The larvae are short legged grubs, fat bodied, curved, and around 1/8 to 1/6 inch long. Adults feed on the foliage, while larvae feed on the roots. This beetle is also known as the clover rootworm.

Imbricated Snout Beetle (Epicaerus imbricatus): Adult beetles are weevils, greenish-gray in color with two irregular light bands across the wing covers, and around 1/2 inch long. Adults feed on foliage, buds, or stems. Larvae live in the roots or stems of plants.
 

Japanese Beetle (Popillia japonica): Adults are metallic green or greenish-bronze with reddish wing covers and around 1/3 to 5/8 inch long; two prominent and several smaller white spots occur near the tip of the abdomen and along the sides. Larvae (grubs) are grayish-white with brown heads, 3/4 to 1 inch long, and are usually found in a curved position. Adults feed on leaves and on the surface of fruit. Larvae feed on the roots of grasses.

 

June Beetles (Phyllaphaga spp.): Adults are reddish-brown to black and around 1 inch long. Grubs are white with the dark contents within the body showing through the skin, around 1/2 to 1 1/2 inches long, have six prominent legs, and the spines on the underside of the tip of the abdomen are in the pattern of an elongated diamond. Adults feed on the foliage of plants, while grubs feed on roots.

Mexican Bean Beetle (Epilachna varivestis): Adult beetles are coppery-yellow with 16 black dots on their backs, 8 on each wing cover; adults have the typical convex shape and are around 1/3 inch long. Larvae are soft, yellow, around 1/3 inch long and half as wide, and have black-tipped spines on the back. Larvae and adults feed on pods, stems, and foliage.

Mottled Tortoise Beetle (Deloyala guttata): Adult beetles are golden around the margins of the elytra, around 5/16 inch long, and their backs are mottled black and yellow. Larvae are dull green, bluish along the back, and covered with broad, branching masses of excrement. Larvae and adults both cause damage; they damage a plant by eating parts of a leaf or entire leaves.

Oriental Beetle (Anomala orientalis): Adults are straw colored with varying dark markings, broad bodied, spiny legged, convex-backed, and around 5/8 inch long; adults feed on the foliage. Larvae are white grubs that feed on the roots; the grubs can be distinguished from japanese beetle grubs by the arrangement of spines in two parallel lines on the underside of the abdomen.

Red Turnip Beetle (Entomoscelis americana): Adults are bright red with black patches on the head and three black lines on the elytra, and around 1/4 inch long. Larvae are orange to black. Larvae and adults feed on plants at night.
 

Rose Chafer Beetle (Macrodactylus subspinosus): Adult beetles are tan with a reddish-brown head, slender, around 1/3 to 1/2 inch long, and have prominent long spiny legs. Larvae resemble white grubs but are thinner, smaller, and can reach 3/4 inch in length. Adults feed on foliage, flowers, and fruit, while larvae feed on the roots.

 

Seedcorn Beetle (Agonoderus lecontei): This beetle is dark brown, striped, and around 1/4 to 1/3 inch long; they eat out the insides of corn kernels, which renders the corn seed useless.

Slender Seedcorn Beetle (Clivina impressifrons): This beetle is similar to the seedcorn beetle except it is chestnut brown in color; it also feeds on corn seed.

Spinach Carrion Beetle (Silpha bituberosa): Adults are black with three longitudinal ridges on each elytron. This beetle is a scavenger beetle. Larvae are white and black and feed on the edges of leaves of a few vegetables.

Spotted Asparagus Beetle (Crioceris duodecimpunctata): Adults are reddish-orange or tan with six prominent black spots on each wing cover; adult beetles feed on the foliage. Larvae are orange in color and only feed on asparagus berries; larvae bore into the developing berry and eat out the pulp and seeds.

Spotted Cucumber Beetle (Diabrotica undecimpunctata howardi): The larvae of this beetle is known as the southern corn rootworm. Adults are greenish-yellow beetles, approximately 1/4 inch long, and have 12 irregular black spots on their backs. Adult beetles feed on the foliage of several vegetables. Larvae are slender, white to cream colored, have a wrinkled body with three pairs of inconspicuous legs, and are 1/2 to 3/4 inch in length; the head and the last segment of the body are dark brown to black with the head being more narrow than the opposite end of the abdomen. Larvae tunnel out roots.

Spotted Cucumber Beetle Larvae - southern corn rootworm

 

Squash Beetle (Epilachna borealis): Adults are yellow with seven black spots on each wing cover. Spiny larvae and adult beetles both feed on the foliage of a few vegetables.

Striped Cucumber Beetle (Acalymma vittata): Adults are yellowish with 3 black stripes, 1/5 inch long, and feed on the foliage of cucurbits; this beetle transmits bacterial wilt of cucurbits and the cucumber mosaic virus. Larvae are white, slender, around 1/3 inch long, and feed on roots and underground parts of stems.

Striped Tortoise Beetle (Agroiconota bivittata): Adults are dull yellow in color with five longitudinal black stripes on the wing covers. The larvae are yellowish-white with a median gray line, have short marginal spines, and a thick tail-like projection that bears the shed skins. Larvae and adults feed on foliage.
 

Sweetpotato Leaf Beetle (Typophorus nigritus viridicyaneus): Adults are metallic blue-green, oblong, and around 1/4 inch long; adults feed on the tender leaves near the crown of a plant. Larvae are pale yellow with 6 small legs, plump, nearly 1/2 inch long, and have a brownish colored head; larvae first burrow through the vine underground and later tunnel through fleshy roots.

Threelined Potato Beetle (Lema trilineata): Adults are reddish-yellow with three broad black stripes on their backs. Larvae have granular masses of excrement all over their bodies. Both larvae and adults feed on the foliage.

Western Spotted Cucumber Beetle (Diabrotica undecimpunctata undecimpunctata): Adults have the same greenish-yellow wing covers as the spotted cucumber beetle, but they are slightly smaller and have larger black spots on their backs. The larvae are similar to the larvae produced by the spotted cucumber beetle. Adults feed on foliage and cut holes in ripening fruit, while larvae feed on roots.

Western Striped Cucumber Beetle (Acalymma trivittata): Adults are similar to the striped cucumber beetle; they have a yellowish body with three black stripes, but the basal portion of the antennae is yellow instead of black. The larvae are similar to the larvae of the striped cucumber beetle. Adults feed on foliage, while the larvae feed on roots.

Whitefringed Beetle (Graphognathus spp.): Adults are dark gray with a short, broad snout, and around 1/2 inch long; the margins of the wing covers are banded with white and there are two pale lines extending along the sides of the head and prothorax, one above the eye and one below it. The body of the adult beetle is covered with dense, short, pale hairs, which get longer toward the tip of the elytra. The adults feed on the margins of older leaves toward their bases. Larvae are yellowish-white, about 1/2 inch long, legless, and are sparsely covered with short hairs; larvae feed on the lower part of a plant stem and taproot.

Yellowmargined Leaf Beetle (Microtheca ochroloma): Adults are small and the brown wing covers have a pale yellow or white margin with four rows of deep pits; adults feed on the margins of leaves and make irregular holes in the terminal growth.